1. Field of the Invention
The present invention generally relates to a power converter, and more particularly, to a power converter having multifunctional pins. The multifunctional pins are adapted for identifying the setting of a slave address of a system management bus (SMBus).
2. Description of Related Art
An SMBus is often required by a pulse width modulation (PWM) power converter for performing power management. FIG. 1 is a circuit block diagram illustrating a conventional power converter 100. Currently, when applying in an interface having an SMBus, a buck PWM power stage often requires additional strapping pins. For example, as shown in FIG. 1, the power converter 100 requires strapping pins ADDR0, ADDR1, ADDR2, ADDR3 . . . for setting an SMBus slave address, so as to achieve the object of voltage management. In view of the SMBus transmission protocol, the power converter 100 is a slave device, and thus should be given with a slave address for communicating with a master device. Referring to FIG. 2, there is shown a correlation table depicting slave addresses of the SMBus which uses strapping pins for setting the power converter 100.
It can be concluded from the conventional techniques as shown in FIGS. 1 and 2 that the conventional power converter 100 uses a plurality of strapping pins for setting a salve address of the SMBus. The slave address is set by employing a resistance to pull high or pull low a logic status, thus selecting the address of the SMBus by permutations and combinations of 0 and 1 of the strapping pins ADDR0 through ADDRn, in which n is an integer greater than 1.
The conventional approach of setting the SMBus slave address has the following disadvantages. First, it requires for at least one strapping pin, and when the address is desired to be selected with more flexibility, more strapping pins are required. When more strapping pins are employed, the packaging cost for the integrated circuit (IC) inevitably increases in accordance with the amount of the increased strapping pins. Further, when more addresses are demanded, more strapping pins are required. This raises problems of amount of pulling out strapping pins and the corresponding packaging cost for semiconductor manufacturers. Restricted by the IC package, current electronic products are designed to be thinner, lighter, shorter and smaller, and therefore it is now more desirable and even becomes a development strategy for the semiconductor manufacturers to reduce the amount of IC pins employed for the power converter than ever before.